Insulation from addition to old construction
So I have an non heated/cooled crawl space above my addition. As you can imagine it gets very hot or cold up there depending on the season. The actual addition is adequately insulated into the living area. However, the part of the addition that covers the old rear of the house is not insulated. This would be the part of the upstairs of the old part of the house. They have cut and run ducting through the roof of the original house that stick into the crawl space of the addition. Its kinda hard to describe and Ill get pics up if needed. Anyway, these holes are allowing cold/hot air from the addition crawlspace into the floor joist area of the upstairs main living area. Can I simply place insulation over the holes or do I need to seal them some other way first? Also, can i just lay insulation over the old roofing as well? THanks!